ACPICA: Fix for Alias operator to see target child objects

Fixed a problem with the Alias operator when the target of the
alias is a named ASL operator that opens a new scope -- Scope,
Device, PowerResource, Processor, and ThermalZone. In these cases,
any children of the original operator could not be accessed via
the alias, potentially causing unexpected AE_NOT_FOUND exceptions.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/executer/excreate.c

@@ -96,16 +96,28 @@ acpi_status acpi_ex_create_alias(struct acpi_walk_state *walk_state)
 	 * to the original Node.
 	 */
 	switch (target_node->type) {
+
+		/* For these types, the sub-object can change dynamically via a Store */
+
 	case ACPI_TYPE_INTEGER:
 	case ACPI_TYPE_STRING:
 	case ACPI_TYPE_BUFFER:
 	case ACPI_TYPE_PACKAGE:
 	case ACPI_TYPE_BUFFER_FIELD:
 
+		/*
+		 * These types open a new scope, so we need the NS node in order to access
+		 * any children.
+		 */
+	case ACPI_TYPE_DEVICE:
+	case ACPI_TYPE_POWER:
+	case ACPI_TYPE_PROCESSOR:
+	case ACPI_TYPE_THERMAL:
+	case ACPI_TYPE_LOCAL_SCOPE:
+
 		/*
 		 * The new alias has the type ALIAS and points to the original
-		 * NS node, not the object itself.  This is because for these
-		 * types, the object can change dynamically via a Store.
+		 * NS node, not the object itself.
 		 */
 		alias_node->type = ACPI_TYPE_LOCAL_ALIAS;
 		alias_node->object =
@@ -115,9 +127,7 @@ acpi_status acpi_ex_create_alias(struct acpi_walk_state *walk_state)
 	case ACPI_TYPE_METHOD:
 
 		/*
-		 * The new alias has the type ALIAS and points to the original
-		 * NS node, not the object itself.  This is because for these
-		 * types, the object can change dynamically via a Store.
+		 * Control method aliases need to be differentiated
 		 */
 		alias_node->type = ACPI_TYPE_LOCAL_METHOD_ALIAS;
 		alias_node->object =

drivers/acpi/namespace/nsaccess.c

@@ -581,6 +581,29 @@ acpi_ns_lookup(union acpi_generic_state *scope_info,
 			return_ACPI_STATUS(status);
 		}
 
+		/* More segments to follow? */
+
+		if (num_segments > 0) {
+			/*
+			 * If we have an alias to an object that opens a scope (such as a
+			 * device or processor), we need to dereference the alias here so that
+			 * we can access any children of the original node (via the remaining
+			 * segments).
+			 */
+			if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
+				if (acpi_ns_opens_scope
+				    (((struct acpi_namespace_node *)this_node->
+				      object)->type)) {
+					this_node =
+					    (struct acpi_namespace_node *)
+					    this_node->object;
+				}
+			}
+		}
+
+		/* Special handling for the last segment (num_segments == 0) */
+
+		else {
 			/*
 			 * Sanity typecheck of the target object:
 			 *
@@ -594,20 +617,20 @@ acpi_ns_lookup(union acpi_generic_state *scope_info,
 			 *
 			 * Then we have a type mismatch. Just warn and ignore it.
 			 */
-		if ((num_segments == 0) &&
-		    (type_to_check_for != ACPI_TYPE_ANY) &&
+			if ((type_to_check_for != ACPI_TYPE_ANY) &&
 			    (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
-		    (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS) &&
-		    (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE) &&
-		    (this_node->type != ACPI_TYPE_ANY) &&
-		    (this_node->type != type_to_check_for)) {
+			    (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
+			    && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
+			    && (this_node->type != ACPI_TYPE_ANY)
+			    && (this_node->type != type_to_check_for)) {
 
 				/* Complain about a type mismatch */
 
 				ACPI_WARNING((AE_INFO,
 					      "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
 					      ACPI_CAST_PTR(char, &simple_name),
-				      acpi_ut_get_type_name(this_node->type),
+					      acpi_ut_get_type_name(this_node->
+								    type),
 					      acpi_ut_get_type_name
 					      (type_to_check_for)));
 			}
@@ -615,11 +638,12 @@ acpi_ns_lookup(union acpi_generic_state *scope_info,
 			/*
 			 * If this is the last name segment and we are not looking for a
 			 * specific type, but the type of found object is known, use that type
-		 * to see if it opens a scope.
+			 * to (later) see if it opens a scope.
 			 */
-		if ((num_segments == 0) && (type == ACPI_TYPE_ANY)) {
+			if (type == ACPI_TYPE_ANY) {
 				type = this_node->type;
 			}
+		}
 
 		/* Point to next name segment and make this node current */